1. Field of the Invention
The present invention relates to topical compositions useful for treating skin discolorations and to methods of use for these compositions.
2. Description of the Background Art
Skin discoloration is a common complaint. Discoloration may occur in any location on the body and frequently occurs under the eyes. Often referred to as infraorbital discoloration, it has also been described as “dark circles”. Discoloration under the eye usually follows the anatomy of the orbicularis oculi muscle, which surrounds the orbital area. While frequently referred to as a pigmentary condition, the cause of this type of discoloration tends to be multifactorial and is more often the result of a combination of factors including skin translucency, vascularity, and heredity/ethnicity.
Because dark circle discoloration most typically follows the muscle surrounding the orbital area, it has most often been attributed to hyperpigmentation. This is not necessarily the cause in all patients, despite attempts to address infra-orbital discoloration as a hyperpigmentation problem in the region of the lower eyelid. Unfortunately, most patients experiencing dark circles have not been examined with respect to identification of the inter-individual anatomic structural elements that can contribute to developing appropriate treatment protocols.
Generally, there are four main categories of causes for dark circles, which can be present in isolation or in combination, including deep vascular congestion/superficial vascularity, hyperpigmentation, skin translucency, and structural shadowing. It is important to differentiate between these various causes in order to appropriately select treatment modalities to achieve a successful outcome.
The rich vascular network located around the medial canthus and nasal periorbital regions is the cause of the appearance of dark circles seen in children and adults with chronic allergies or sinus disease. Typically referred to as “allergic shiners”, these bluish discolorations in the orbitopalpebral groove are caused by chrome congestion of the nasal and paranasal cavities.
A complex superficial vascular network exists within the dermis of the eyelid. When these small, subcutaneous vessels become visible they lend a reddish discoloration to the area. Visibility may result from chronic eye rubbing, which creates repeated superficial trauma to the area. Rubbing of the eyes may also lead to deposition of pigment.
Hyper-pigmentation occurs in a semicircular pattern involving the lower eyelid and may result from a multitude of focal or systemic conditions. Post inflammatory hyperpigmentation can cause pigment accumulation in a superficial (more commonly) or deep (severe cases) pattern. Inflammatory conditions that disrupt the deep dermal-epidermal junction often heal with melanin deposition in the dermal macrophages where turnover of melanin is extremely slow. If severe, other types of inflammatory conditions such as allergic dermatitis, trauma, drug eruptions, and photocontact dermatitis can lead to disruption in the dermoepidermal junction.
Hyperpigmentation can also result from non-inflammatory lesions of the peri-orbital area. Examples of these conditions include melasma, ephelides, lentigo simplex, juntional nevi, solar lentigines (“liver spots”), and nevi. Systemic conditions that can lead to pigmentation of the penorbital area include various metabolic and endocrine disorders.
The skin of the eyelids and periorbital area is markedly thin in comparison to skin elsewhere on the face. Additionally, the skin becomes even thinner with aging, causing it to become more translucent. The vascular network underlying the surface becomes visible and lends a reddish-blue hue to the periorbital area. This is especially true in the area of the infraorbital rim where the lack of structural fat and muscle found elsewhere on the face places the coloration in relief against the underlying bone.
Multiple anatomical aspects of the peri-orbital area can create shadows in the infra-orbital area. Classically, deeply set orbits can cause shadowing resulting in discoloration in the infra-orbital area. With prolapse of the infraorbital fat and a prominent naso fugal fold, the double convex contour of the infraorbital area creates a color change, which may be structural and vascular. This contour creates a shadow in the underlying tear trough. Shadows can also occur from other facial structures, such as a steep nasal bridge, prominent frontal bossing deeply set eyes, or enophthalmos.
The skin of the lower eyelid is contiguous with that of the upper cheek/malar area. With aging, the mid-face descends due to loss of support by the lateral component of the orbitomalar ligament and loss of volume. With this descent of the midface, a tear trough deformity is created and therefore a “dark circle”.
Exfoliating and bleaching creams have been used to address superficial hyper pigmentation. If examination determines that pigment is superficial, exfoliating creams (such as retinoic acid) and bleaching creams (containing hydroquinones) have been used to exfoliate and lighten and lessen pigment deposition. Further addition of an exfoliating agent to the regimen has been reported to result in a synergistic effect. Unfortunately, use of hydroquinone is not always successful in fading lesions and in most cases the original discoloration returns.
Regardless of the source of the pigment, it usually takes a minimum of three weeks to a few months before results are visible. Furthermore, in preparations containing hydroquinone, the higher the concentration of hydroquinone, the greater the incidence of side effects, such as dermatitis. Combination treatments with an added corticosteroid cream have sometimes been used to decrease the incidence of dermatitis; however, caution must be taken with prolonged use of corticosteroids on the face, because telangiectasia, atrophy or acne rosacea may develop. Skin atrophy may also be an issue in the already thin skin of the periorbital region.
Allergic reactions are always a consideration for agents applied directly to the skin. It is therefore important to patch test for allergy with hydroquinones. Additionally, sun exposure must be kept to a minimum with tretinoin and hydroquinones and patients are advised to use sunscreen, sunglasses and hats on a regular basis.
Intense Pulsed Light (IPL) utilizes specific wavelengths of light directed to a small area to accomplish its effect. IPL can improve a variety of benign skin imperfections such as superficial and deeper pigment, telangectatic changes of the skin (such as with rosacea), and even unwanted hair.
Chemical peels have been used to treat dark circles mainly attributed to hyperpigmentation. A variety of solutions may be used to perform chemical peeling, including (in increasing order of strength): trichloroacetic acid 35%, trichloroacetic acid 50%, phenol 89%, and Baker's phenol formula. The stronger the chemical, the deeper the peel with greater effects but with increasing risk and longer recovery.
Potential side effects of chemical peels include erythema, infection, hypopigmentation, cicatricial eetropion, scarring, ocular damage, and splotchy hyperpigmentation.
Laser therapy targets hyper pigmentation in the infraorbital area. Little has been reported in the area of pigment-targeted laser treatments for dark circles.
Electro-Optical Synergy technology (ELOS™) is a recent advance in the treatment of pigmented and vascular dyschromia. The theory behind this new technology stems from the theoretical limits of the light based technologies. Combining two types of energies, optical and electrical, (conducted radiofrequency) allows the use of less optical energy at a level that is safe even for dark skin.
The role of surgical intervention in treating skin discolorations is primarily targeted to treating the structural causes of dark circles, such as shadowing from inferior orbital herniated fat, malar hypoplasia, and/or tear trough deformity. These conditions, either in isolation or in concert, can be treated by lower eyelid blepharoplasty with or without fat transposition, meloplication, midface elevation, and/or facial fat injections. Each is addressed with differing or multiple procedures depending on the patient's underlying structure.
There are a multitude of skin products on the market, many with claims to reduce the appearance of skin discolorations, particularly “age-spots.” Eye care preparations are particularly popular, and include products by almost every major cosmetic company. Some contain hydroquinones, but most include various humectants and skin softeners. An example of a product that touts use of all-natural ingredients is a “Restorative Eye Gel” containing botanical extracts including Butcher's Broom, Horsechestnut, D-beta glucosamine and Spin Trap™. One of the ingredients, the Butcher's Broom Extract, is said to have a vasoconstrictor effect by purportedly strengthening capillary walls, while the combination of extracts is said to reduce puffiness and prevent further skin aging (Bydoctorsonly cosmetic products).
Methods for treating and preventing undesired pigmentation of the skin are described in U.S. Pat. No. 6,503,523, where the compositions include vitamin A related compounds in combination with various ubiquinones.